very interesting article. i was particularly intrigued by this little quotation, near the end :

that sounds very interesting. i wonder how exactly they plan to implement that ? it will certainly help to make more content available for the sony, which is currently one of the biggest complaints it would seem.

ePUB and PDF support would seem to satisfy this requirement already. They are not likely to get mobipocket. What else do you expect them to get? Perhaps FBReader ported would give them practically everything else.